摘要
The Democratic Republic of the Congo holds important reserves of oil shale which is still under geological status.Herein,the characterization and pyrolysis kinetics of typeⅠkerogen-rich oil shale of the western Central Kongo(CK)were investigated.X-ray diffraction,Fourier-transform infrared spectroscopy and thermal analysis(TG/DTA)showed that CK oil shale exhibits a siliceous mineral matrix with a consistent organic matter rich in aliphatic chains.The pyrolysis behavior of kerogen revealed the presence of a single mass loss between 300 and 550°C,estimated at 12.5%and attributed to the oil production stage.Non-isothermal kinetics was performed by determining the activation energy using the iterative isoconversional model-free methods and exhibits a constant value with E=211.5±4.7 kJ mol.1.The most probable kinetic model describing the kerogen pyrolysis mechanism was obtained using the Coats–Redfern and Arrhenius plot methods.The results showed a unique kinetic triplet confirming the nature of kerogen,predominantly typeⅠand reinforcing the previously reported geochemical characteristics of the CK oil shale.Besides,the calculation of thermodynamic parameters(ΔH~*,ΔS~*andΔG~*)corresponding to the pyrolysis of typeⅠkerogen revealed that the process is non-spontaneous,in agreement with DTA experiments.
The Democratic Republic of the Congo holds important reserves of oil shale which is still under geological status. Herein, the characterization and pyrolysis kinetics of type Ⅰ kerogen-rich oil shale of the western Central Kongo(CK) were investigated.X-ray diffraction, Fourier-transform infrared spectroscopy and thermal analysis(TG/DTA) showed that CK oil shale exhibits a siliceous mineral matrix with a consistent organic matter rich in aliphatic chains. The pyrolysis behavior of kerogen revealed the presence of a single mass loss between 300 and 550 °C, estimated at 12.5% and attributed to the oil production stage.Non-isothermal kinetics was performed by determining the activation energy using the iterative isoconversional model-free methods and exhibits a constant value with E = 211.5 ± 4.7 kJ mol.1. The most probable kinetic model describing the kerogen pyrolysis mechanism was obtained using the Coats–Redfern and Arrhenius plot methods. The results showed a unique kinetic triplet confirming the nature of kerogen, predominantly type Ⅰ and reinforcing the previously reported geochemical characteristics of the CK oil shale. Besides, the calculation of thermodynamic parameters(ΔH~*, ΔS~* and ΔG~*) corresponding to the pyrolysis of type Ⅰ kerogen revealed that the process is non-spontaneous, in agreement with DTA experiments.
基金
financially supported by University of Mohammed V-Morocco under the Project No.SCH 04/09 and HassanⅡAcademy of Science and Technology,Morocco.
